Inner bladder structure for ball

ABSTRACT

A ball inner bladder structure, particularly suitable for a seamless ball, includes a bladder in the form of a spherical bag, a yarn layer enclosing the bladder, an emulsion layer applied over the yarn layer, and a ball cover layer bonded to the emulsion layer. The yarn layer is an integrally knitted web structure having a 3D spherical shape. Knitted yarns subjected to pressure can displace relative to one another to finely adjust a surface configuration of the web structure for the same to completely bear against the bladder. The emulsion layer fills up voids on the yarn layer to provide a smooth spherical surface. The specifically knitted yarn layer can effectively control an expansion degree of the bladder when the same is inflated. And, expansion or compression pressure applied to the bladder is uniformly distributed over interlocking points of knitted yarns, preventing the bladder from deformation and breaking.

FIELD OF THE INVENTION

The present invention relates to an inner bladder structure for seamless ball, and more particularly to a ball inner bladder structure that includes a yarn layer formed in a specific knitting and stitching manner.

BACKGROUND OF THE INVENTION

There are various types of balls. Some balls with a relatively simple structure can include a hollow spherical body directly molded using a rubber material. The hollow spherical body inflated with air is swollen to form an elastic ball. For the purpose of providing the balls with required appearance and touch, and of easily distinguishing different types of balls from one another, the balls can further include a multi-layer structure having an inner bladder and an outer cover layer attached to an outer surface of the inner bladder. The inner bladder as a main structure for supporting the ball can be manufactured in many different ways.

In a conventional technique for manufacturing a ball with an inner bladder, a bladder made of a rubber material and a bonded fabric layer together constitute a spherical structure. In the first conventional ball manufacturing technique, a whole piece of fabric is cut into a plurality of smaller pieces having the same predetermined shape. The cut fabric pieces are applied with an adhesive and then bonded to an outer surface of the rubber bladder in a specific arrangement. After the cut fabric pieces have been bonded to the whole outer surface of the rubber bladder, the adhesive is heat dried and the bladder is inflated to adjust an overall shape thereof. However, the bonded joints at the overlapped edges of the fabric pieces have relatively weak structural strength, and the bonded fabric layer tends to deform or have separated fabric pieces due to a shearing action. Further, the bonded joints have increased thickness due to the overlapped edges of the fabric pieces and accordingly reduce the roundness of the ball so formed.

In another conventional ball manufacturing technique, a rubber bladder and a stitched fabric layer together constitute a spherical structure. In this conventional ball manufacturing technique, a whole piece of fabric is cut into a plurality of smaller pieces having the same predetermined shape. The cut fabric pieces are stitched together to form a spherical bag, and the rubber bladder is inserted in the spherical bag and bonded to the spherical bag using an adhesive material. The adhesive material is heat dried and the rubber bladder is inflated to adjust an overall shape thereof. With the cut fabric pieces being stitched together, the stitched joints can have increased structural strength. However, the stitched joints still have increased thickness to thereby reduce the roundness of the ball so formed.

In a further conventional ball manufacturing technique, a rubber bladder and a wound yarn layer together constitute a spherical structure. In this conventional ball manufacturing technique, the rubber bladder is inflated to adjust an overall shape thereof, and then yarns coated with adhesive are randomly wound around an outer surface of the inflated rubber bladder. When the rubber bladder has been completely wound by the yarns to have a yarn layer formed thereon, the adhesive is heat dried and the overall shape of the bladder is adjusted again. With this manufacturing technique, a ball with high roundness can be obtained. However, since the yarns are glued to the outer surface of the rubber bladder only by the adhesive coated on the yarns, the wound yarn layer so formed has further reduced tensile strength and shearing strength.

According to the above-described conventional ball manufacturing techniques, for the purpose of maintaining or increasing the structural strength of the ball inner bladder and of protecting the ball inner bladder against deformation under pressure, the outer surface of the rubber bladder is bound and reinforced using fabric pieces or yarns. However, the overlapped edges of the fabric pieces are not easily perfectly firmly bonded together at the bonded joints that tend to dislocate or deviated due to a shearing action; and the bonded or the stitched joints have relatively increased thickness to reduce the roundness of the ball so formed. Therefore, it is necessary to improve the conventional inner bladder structures for ball.

SUMMARY OF THE INVENTION

A primary object of the present invention is to provide an improved inner bladder structure for ball. The inner bladder structure includes a yarn layer formed in a specific knitting and stitching manner to effectively control an expansion degree of an inflatable bladder enclosed in the yarn layer. Expansion and compression pressure applied to the bladder is uniformly distributed over interlocking points of knitted yarns, so that the bladder is not easily subject to deformation and breaking.

To achieve the above and other objects, the inner bladder structure for ball according to the present invention includes a bladder in the form of a spherical bag for using as a main body structure of a seamless ball, a yarn layer provided on an outer surface of the bladder, an emulsion layer provided on an outer surface of the yarn layer to serve as a binding material, and a round and smooth ball cover layer bonded to an outer surface of the emulsion layer. The yarn layer is a single-layered web structure integrally knitted using a plurality of yarns to have a three-dimensional (3D) spherical shape, so that a plurality of voids is formed between adjacent knitting yarns. And, the emulsion layer fills up the voids on the yarn layer to form a complete spherical body.

In a preferred embodiment, the web structure of the yarn layer is formed by knitting the yarns around the bladder from a predetermined starting point on the outer surface of the bladder, so that the web structure has a plurality of interlocking points of the yarns and is radially outward expanded from the starting point to gradually increase a winding radius thereof at a fixed spacing. When the winding radius of the web structure is equal to a radius of the bladder, the knitting continues toward another point on the bladder diametrically opposite to the starting point while the winding radius of the web structure gradually decreases at the same fixed spacing. And, when the web structure is finally extended to the diametrically opposite point on the bladder, a spherical-shaped web structure is completed.

Each of the interlocking points is formed at an intersection of four knitting yarns that are connected to one another at the intersection and extended in four different directions, it is therefore able to control an elongation ratio and an expansion degree at the interlocking point when the same is subjected to stress from different directions. The ball cover layer includes an inner filler layer and an outer cover layer. The inner filler layer is in direct contact with and glued to the outer surface of the emulsion layer, and the outer cover layer is formed from a plurality of panels that have the same predetermined shape and are arranged adjoining one another. In a preferred embodiment, the outer cover layer is made of thermoplastic polyurethane (TPU), the filler layer is made of ethylene vinyl acetate (EVA), and the yarn layer is formed using synthetic twist yarns.

In another preferred embodiment, the yarn layer is in the form of a spherical-shaped knitted fabric. The spherical-shaped knitted fabric is formed by knitting yarns at a fixed spacing and around an axis of a preset spherical surface, which has a radius corresponding to that of the bladder, and the knitting is started from a preset one of the longitudes of the preset spherical surface.

In a preferred embodiment, the spherical-shaped knitted fabric includes a plurality of knitting yarns, which are repeatedly bent to form a plurality of loop portions. The loop portions are respectively extended through a loop portion formed by a previous adjacent knitting yarn, and are then respectively extended through by another loop portion formed by a next adjacent knitting yarn, so that a web structure is formed with a void formed in each loop portion and between any two laterally adjacent loop portions. Therefore, when the spherical-shaped knitted fabric is subjected to an external force, the knitting yarns thereof can displace relative to one another to thereby adjust the surface configuration of the spherical-shaped knitted fabric.

The inner bladder structure for ball according to the present invention is characterized in that the yarn layer is formed in a specific knitting and stitching manner to have few or no seams, so that the yarn layer can effectively control the expansion degree of the bladder when the same is inflated. Moreover, when the bladder is inflated to expand or is compressed under an external force, pressure from such expansion or compression is uniformly distributed over the interlocking points of yarns on the yarn layer, so that the bladder is not easily subject to deformation and breaking.

BRIEF DESCRIPTION OF THE DRAWINGS

The structure and the technical means adopted by the present invention to achieve the above and other objects can be best understood by referring to the following detailed description of the preferred embodiments and the accompanying drawings, wherein

FIG. 1 is a cutaway view of a ball with an inner bladder structure according to a preferred embodiment of the present invention;

FIG. 2 schematically shows the forming of a yarn layer over a bladder by knitting yarns on an outer surface of the bladder from a preset starting point on the bladder;

FIG. 3 shows the knitting of the yarn layer on the outer surface of the bladder toward another point diametrically opposite to the starting point;

FIG. 4 shows the yarn layer over the bladder is competed and cast off at the opposite point;

FIG. 5 is a perspective view showing the bladder is completely covered by the knitted yarn layer;

FIG. 6 shows an emulsion layer is applied on an outer surface of the yarn layer;

FIG. 7 shows a ball cover layer is bonded to an outer surface of the emulsion layer shown in FIG. 6;

FIG. 8 is a perspective view showing a spherical-shaped knitted fabric for forming the yarn layer of an inner bladder structure according to a second embodiment of the present invention;

FIG. 9 is an enlarged view of the circled area A of FIG. 8;

FIG. 10 shows a bladder is inserted in the spherical-shaped knitted fabric of FIG. 8;

FIG. 11 shows the spherical-shaped knitted fabric of FIG. 10 is closed by stitching;

FIG. 12 shows two locating sections are removed from the closed spherical-shaped knitted fabric; and

FIG. 13 is an enlarged view of the circled area B of FIG. 12.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will now be described with some preferred embodiments thereof. For the purpose of easy to understand, elements that are the same in the preferred embodiments are denoted by the same reference numerals.

Please refer to FIG. 1 that is a cutaway view of a ball with an inner bladder structure according to a first embodiment of the present invention. The inner bladder structure according to the present invention is particularly suitable for a seamless ball. In the illustrated first embodiment, the inner bladder structure for ball includes a bladder 10, a yarn layer 11, an emulsion layer 12, and a ball cover layer 13. The bladder 10 is in the form of a spherical bag and forms a main body structure of a seamless ball. The spherical bag can be inflated to form a spherical body.

Please refer to FIG. 2. In the first embodiment of the present invention, the yarn layer 11 is a single-layered web structure integrally knitted using knitting yarns 112 to have a three-dimensional (3D) spherical shape, so that the web structure bearing on an outer surface of the bladder 10 has minimized seams. A plurality of voids 113 is formed between adjacent knitting yarns 112, so that the knitting yarns 112 subjected to an externally applied force are displaceable relative to one another, allowing the web structure to finely adjust its surface shape and completely bear against the outer surface of the bladder 10 to ensure the highest possible roundness of the bladder 10. The emulsion layer 12 fills up all the voids 113 on the yarn layer 11 to form a smooth spherical body.

In a preferred embodiment, the web structure of the yarn layer 11 is formed by knitting the yarns 112 around the bladder 10 from a predetermined starting point 110 on the outer surface of the bladder 10, so that the web structure has a plurality of interlocking points 111 of the knitting yarns 112 and is radially outward expanded from the starting point 110 to gradually increase a winding radius thereof at a fixed spacing. Then, when the winding radius of the web structure is equal to a radius of the bladder 10, the knitting continues toward another point on the bladder 10 diametrically opposite to the starting point 110 while the winding radius of the web structure gradually decreases at the same fixed spacing. And, when the web structure is finally extended to the diametrically opposite point on the bladder 10, the spherical-shaped web structure is completed.

Please refer to FIG. 3. In the illustrated first embodiment, each of the interlocking points 111 is formed at an intersection of four knitting yarns 112 that are connected to one another at the intersection and extended in four different directions. In this manner, it is able to control an elongation ratio and an expansion degree at the interlocking point 111 when the same is subjected to stress from different directions. However, it is understood the above embodiment is illustrated only as an exemplification and is not intended to restrict the present invention. That is, the interlocking point 111 may be otherwise formed at an interaction of more than four knitting yarns 112.

The yarn layer 11 is formed using synthetic twist yarns. With the yarn layer 11, pressure from internal expansion and external compression can be uniformly distributed over the bladder 10, so that the bladder 10 is protected against deformation or breaking under such pressure.

The ball cover layer 13 is glued to an outer surface of the emulsion layer 12, and includes an inner filler layer 14 and an outer cover layer 15. The inner filler layer 14 is in direct contact with and glued to the outer surface of the emulsion layer 12. The outer cover layer 15 is formed from a plurality of panels that have the same predetermined shape and are arranged adjoining one another. In a preferred embodiment, the outer cover layer 15 is made of thermoplastic polyurethane (TPU), and the inner filler layer 14 is made of ethylene vinyl acetate (EVA).

Please refer to FIG. 8. According to a second embodiment of the present invention, the yarn layer 11 is in the form of a spherical-shaped knitted fabric 20. The spherical-shaped knitted fabric 20 is formed by knitting yarns at a fixed spacing around an axis of a preset spherical surface, which has a radius corresponding to that of the bladder 10, and the knitting is started from a preset one of the longitudes of the preset spherical surface. The spherical-shaped knitted fabric 20 is knitted using an elastic 3D knitting technique, and has a locating section 21 formed at each of two opposing edges thereof. A releasable connecting yarn 22 is provided between each of the locating sections 21 and the spherical-shaped knitted fabric 20 to form a separable joint 221 thereat, so as to facilitate later separating of the locating sections 21 from the spherical-shaped knitted fabric 20.

FIG. 9 is an enlarged view of the circled area A of FIG. 8. As shown, in the illustrated second embodiment of the present invention, the spherical-shaped knitted fabric 20 includes a plurality of knitting yarns 112, which are repeatedly bent to form a plurality of loop portions 116. The loop portions 116 are respectively extended through a loop portion 116 formed by a previous adjacent knitting yarn 112, and are then respectively extended through by another loop portion 116 formed by a next adjacent knitting yarn 112, so that a web structure is formed with a void 113 formed in each loop portion 116 and between any two laterally adjacent loop portions 116. With this structure, when the spherical-shaped knitted fabric 20 is subjected to an external force, the knitting yarns 112 can displace relative to one another to thereby adjust the surface configuration of the spherical-shaped knitted fabric 20.

Please refer to FIGS. 2 to 7. To produce the inner bladder structure for ball according to the first embodiment of the present invention, first prepare yarns and knit the same into the spherical-shaped yarn layer 11. An elastic opening 115 is formed at a cast-off end of the spherical-shaped yarn layer 11 with a length of yarn 114 extended from and left at the elastic opening 115. Then, insert the bladder 10 in the yarn layer 11 via the elastic opening 115 and inflate the bladder 10, so that the bladder 10 has an outer surface tightly contacting with the yarn layer 11. Then, the elastic opening 115 is closed and held in place by knitting the length of yarn 114 thereat. Then, apply the emulsion layer 12 on the outer surface of the yarn layer 11 to fill up the voids 113 on the yarn layer 11. The emulsion layer 12 is then heat dried, and a complete and smooth spherical structure is obtained. Finally, the ball cover layer 13, which is formed from an upper and a lower half ball cover, is bonded to the outer surface of the emulsion layer 12 through thermosetting to thereby form a seamless ball.

Please refer to FIGS. 10 to 13. To produce the inner bladder structure for ball according to the second embodiment of the present invention, in which the yarn layer 11 is in the form of a spherical-shaped knitted fabric 20, first position the inflated bladder 10 in a space defined by the spherical-shaped knitted fabric 20 and then pull the spherical-shaped knitted fabric 20 for the same to tightly contact with the outer surface of the bladder 10. Then, the two opposing edges of the spherical-shaped knitted fabric 20 are stitched together using a stitching yarn 23, and the releasable connecting yarns 22 are removed to separate the locating sections 21 from the spherical-shaped knitted fabric 20. When the spherical-shaped knitted fabric 20 is subjected to an external force, the knitting yarns 112 can displace relative to one another to thereby adjust the surface configuration of the spherical-shaped knitted fabric 20, allowing the spherical-shaped knitted fabric 20 to fitly bear against the outer surface of the bladder 10.

After the spherical-shaped knitted fabric 20 has fitly attached to the outer surface of the bladder 10, the emulsion layer 12 is applied over the outer surface of the spherical-shaped knitted fabric 20 to fill up the voids 113 thereof in the same way as that shown in FIG. 6. The emulsion layer 12 is then heat dried, and a complete and smooth spherical structure is obtained. Finally, the ball cover layer 13, which is formed from an upper and a lower half ball cover, is bonded to the outer surface of the emulsion layer 12 through thermosetting to thereby form a seamless ball.

In brief, in the inner bladder structure for ball according to the present invention, the yarn layer is formed by knitting and stitching in a specific manner to effectively control the expansion degree of the bladder when the same is inflated. In addition, when the bladder is inflated to expand or is compressed under an external force, the pressure from such expansion or compression is uniformly distributed over the interlocking points, so that the bladder is not easily subject to deformation and breaking.

The present invention has been described with some preferred embodiments thereof and it is understood that many changes and modifications in the described embodiments can be carried out without departing from the scope and the spirit of the invention that is intended to be limited only by the appended claims. 

1. An inner bladder structure for ball, particularly suitable for a seamless ball, comprising a bladder being in the form of a spherical bag and forming a main body structure of a seamless ball, a yarn layer being provided on an outer surface of the bladder, an emulsion layer being provided on an outer surface of the yarn layer to serve as a binding material, and a round and smooth ball cover layer bonded to an outer surface of the emulsion layer; the yarn layer being a single-layered web structure integrally knitted using a plurality of yarns to have a three-dimensional (3D) spherical shape with a plurality of voids formed between adjacent knitting yarns; and the emulsion layer filling up the voids on the yarn layer to form a complete spherical body.
 2. The inner bladder structure for ball as claimed in claim 1, wherein the web structure of the yarn layer is formed by knitting the yarns around the bladder from a predetermined starting point on the outer surface of the bladder, so that the web structure has a plurality of interlocking points of the yarns and is radially outward expanded from the starting point to gradually increase a winding radius thereof at a fixed spacing; and wherein when the winding radius of the web structure is equal to a radius of the bladder, the knitting continues toward another point on the bladder diametrically opposite to the starting point while the winding radius of the web structure gradually decreases at the same fixed spacing, and when the web structure is finally extended to the diametrically opposite point on the bladder, the spherical-shaped web structure is completed.
 3. The inner bladder structure for ball as claimed in claim 2, wherein each of the interlocking points is formed at an intersection of four knitting yarns that are connected to one another at the intersection and extended in four different directions, it is therefore able to control an elongation ratio and expansion degree at the interlocking point when the same is subjected to stress from different directions.
 4. The inner bladder structure for ball as claimed in claim 1, wherein the ball cover layer includes an inner filler layer and an outer cover layer; the inner filler layer being in direct contact with and glued to the outer surface of the emulsion layer, and the outer cover layer being formed from a plurality of panels that have the same predetermined shape and are arranged adjoining one another.
 5. The inner bladder structure for ball as claimed in claim 4, wherein the outer cover layer is made of thermoplastic polyurethane (TPU), and the inner filler layer is made of ethylene vinyl acetate (EVA).
 6. The inner bladder structure for ball as claimed in claim 1, wherein the yarn layer is formed using synthetic twist yarns.
 7. The inner bladder structure for ball as claimed in claim 1, wherein the yarn layer is in the form of a spherical-shaped knitted fabric; the spherical-shaped knitted fabric being formed by knitting at a fixed spacing around an axis of a preset spherical surface, which has a radius corresponding to that of the bladder, and the knitting being started from a preset one of the longitudes of the preset spherical surface.
 8. The inner bladder structure for ball as claimed in claim 7, wherein the spherical-shaped knitted fabric includes a plurality of knitting yarns, which are repeatedly bent to form a plurality of loop portions; the loop portions being respectively extended through a loop portion formed by a previous adjacent knitting yarn, and then being respectively extended through by another loop portion formed by a next adjacent knitting yarn, so that a web structure is formed with a void formed in each loop portion and between any two laterally adjacent loop portions.
 9. The inner bladder structure for ball as claimed in claim 7, wherein the ball cover layer includes a filler layer and an outer cover layer; the filler layer being in direct contact and glued to the outer surface of the emulsion layer, and the outer cover layer being formed from a plurality of panels that have the same predetermined shape and are arranged adjoining one another.
 10. The inner bladder structure for ball as claimed in claim 9, wherein the outer cover layer is made of thermoplastic polyurethane (TPU), and the filler layer is made of ethylene vinyl acetate (EVA).
 11. The inner bladder structure for ball as claimed in claim 7, wherein the yarn layer is formed using synthetic twist yarns. 